AG Scientific Bromophenol Blue [3,3",5,5"-Tetrabromo-ph

Bromophenol blue is commonly used as a pH indicator, a color marker to monitor the progress of agarose or polyacrylamide gel electrophoresis, and a dye to detect proteins and nucleic acids (absorbance at 610 nm), particularly when staining living tissues.

As an acid-base indicator its useful pH range is 3-4.6 where the color changes from yellow at pH 3.0 to purple at pH 4.6.